3,4-dihydro-2H-pyran → 6-Chloro-1-(tetrahydro-pyran-2-yl)-1H-indazole-3-carboxylic acid methyl ester

Participants

Reaction Steps

To a slurry of 6-Chloro-1H-indazole-3-carboxylic acid methyl ester (8.3 g, 39.5 mmol) in MeCN (200 mL) was added 3,4-Dihydro-2H-pyran (5.4 mL, 59.3 mmol) and p-toluenesulfonic acid (237 mg, 1.25 mmol). After letting the reaction stir for 10 minutes, saturated NaHCO3 (1 mL) was added and the solvent was removed by rotary evaporation to a volume of 100 mL. The mixture was diluted with EtOAc and washed with water (50 mL) and then with saturated NaCl (50 mL). The organic layer was then dried over Na2SO4. After the solids were removed by filtration, the organic layer was concentrated to an oil by rotary evaporation. The product was precipitated from the oil using hexanes to yield the desired product (7.667 g, 66% yield).

Provenance & Evidence